These clean energy funds are generating about $500 million a year, according to a report from the Brookings Institute.

Funded by utility surcharges and other sources, they are responsible for financing thousands of clean energy and efficiency projects.

The Brookings study points out how those funds could accelerate investment even more. They currently emphasize a project finance model, providing production incentives and grants/rebates for projects.

But to build a statewide clean energy industry, they should also support research and development funding, early-stage cleantech companies and emerging technologies, and various other industry development efforts.